How to do "filter select" in an existing selection?
Use the Outliner area to filter by type:


Change the Outliner's display type to Same Types, to filter by type similar to last selected object,
Press A to highlight all items, or LMB on empty part of a line to highlight individual item.
Press RMB on the Outliner, then click Select to select all highlighted items. You can also directly select/deselect an item by clicking LMB or Shift-LMB on its icon.


Use the Outliner's live search feature to filter by name. Even though a little trickier because it also matches object data, vertex groups, etc., selection using it can still be made easier if combined with some Outliner display types like Visible Layers, Selected, or Same Types.

Use the Outliner's Selected display type to prune existing selections.

Maybe those solutions aren't quite what you're looking for, but it's easy enough to try and still very useful to manage complex scenes.